In May 1861, several more states formally seceded from the Union and joined the Confederate States of America. Federal forces also continued to mobilize for the upcoming armed conflict with troops reinforcing major cites, including Washington, DC, and Baltimore, Maryland, both of which could be reached by rivers flowing into the Chesapeake Bay.

At the mouth of the Chesapeake Bay, stood one of the largest and heavily fortified fortresses in the United States, Fortress Monroe. Situated at the tip of a small thin peninsula the large fort, constructed between 1819 and 1861, the fort guarded the entrance to the Elizabeth and James Rivers thereby protecting the cities of Newport News, Norfolk, Portsmouth, and the Gosport Navy Yard, the center of Federal shipbuilding and home to a large part of the United States Navy.

Following Virginia’s secession, Union forces withdrew from the Gosport Navy Yard to Fortress Monroe. The area came under Confederate control but the large stone Fortress Monroe remained in Union hands throughout the war.